rb_id_serial_to_id: return unregistered ID as an internal ID

```ruby
def foo(*); ->{ super }; end
```

This code makes anonymous parameters which is not registered as an
ID.  The problem is that when Ractors try to scan `getlocal`
instructions, it puts the Symbol corresponding to the parameter
in to a hash.  Since it is not registered, we end up with a
strange exception.  This commit wraps the unregistered ID in an
internal ID so that we get the same exception for `...` as `*`.

Co-Authored-By: Aaron Patterson <tenderlove@ruby-lang.org>
Co-Authored-By: John Hawthorn <john@hawthorn.email>

1 files changed, 36 insertions, 0 deletions

diff --git a/bootstraptest/test_ractor.rb b/bootstraptest/test_ractor.rb
index bf80b94cc7..ef1e6afcac 100644
--- a/bootstraptest/test_ractor.rb
+++ b/bootstraptest/test_ractor.rb
@@ -1502,4 +1502,40 @@ assert_equal "ok", %q{
   "ok"
 }
 
+assert_equal "ok", %q{
+  def foo(*); ->{ super }; end
+  begin
+    Ractor.make_shareable(foo)
+  rescue Ractor::IsolationError
+    "ok"
+  end
+}
+
+assert_equal "ok", %q{
+  def foo(**); ->{ super }; end
+  begin
+    Ractor.make_shareable(foo)
+  rescue Ractor::IsolationError
+    "ok"
+  end
+}
+
+assert_equal "ok", %q{
+  def foo(...); ->{ super }; end
+  begin
+    Ractor.make_shareable(foo)
+  rescue Ractor::IsolationError
+    "ok"
+  end
+}
+
+assert_equal "ok", %q{
+  def foo((x), (y)); ->{ super }; end
+  begin
+    Ractor.make_shareable(foo([], []))
+  rescue Ractor::IsolationError
+    "ok"
+  end
+}
+
 end # if !ENV['GITHUB_WORKFLOW']